The sub‐clustering of ECs revealed six subtypes, including extra‐alveolar capillary EC (cEC) (FCN3+EDN1+PLVAP+), alveolar cEC (HPGD+EDNRB+IL1RL1+), arterial EC(GJA5+FBLN5+DKK2), lymphatic EC (CCL21+TFF3+FABP4), INSR+ tumour EC (INSRhiHSPG2+PLVAP+), and ACKR1+ tumour EC (ACKR1+SELP+IL1R1+) (Figure 5A). The gene discussed is CCL21; the disease is neoplasm.